Apart from the bankers, there was Charlotte de Rothschild (1819-1884) who founded the Home for Aged Incurables and the Jews' Emigration Society; Nathaniel de Rothschild (1812-1870), who bought the land near Bordeaux that became the Château Mouton Rothschild vineyards; and Arthur de Rothschild (1851-1903), a philatelist.

Gustave chose art from the outset, not only joining the Impressionists but buying their works and often supporting them with loans; on the side, he was a philatelist, a yachtsman and boat designer, and, like his friend Monet, a passionate gardener.